Polymorph or Multiform Erythema: Symptoms, Diagnosis, Causes, Treatment and Prognosis

A skin lesion: Polymorphous or Multiform Erythema.

It is a skin condition of unknown cause; it is a type of lesion possibly mediated by the deposition of immune complexes in the superficial microvasculature of the skin and the oral mucous membrane that generally follows an infection or exposure to the drug.

It is an uncommon disorder, with a maximum incidence in the second and third decades of life. The disease has several forms or presentations. Hence its name reflects it (multiform, “multiform,” in various ways).

Injuries are a typical manifestation of it. Two types are recognized: mild to moderate and severe (erythema multiforme minor and Erythema multiforme greater).

Signs and symptoms

The condition varies from a mild, self-limited skin rash (Erythema multiforme minor) to a severe and life-threatening form known as erythema multiforme, affecting the mucous membranes.

General symptoms

There are usually no prodromal symptoms in minor erythema multiforme. However, primary erythema multiforme may be preceded by mild symptoms, such as fever or chills, joint weakness, or pain.

Skin lesions

Usually, in erythema multiforme, few or hundreds of skin lesions appear within 24 hours.


Lesions are seen for the first time on the back of the hands and the top of the feet and then extend along the extremities towards the trunk.

The upper extremities are more commonly affected than the lower extremities. Palms and plants may be involved.

The face, neck, and trunk are familiar places. Cutaneous lesions are often grouped on elbows and knees. There may be a mild associated itching or burning sensation.

The initial lesions are restricted, are round, red/pink, and flat (macules), which rise (papules / palpable) and gradually enlarge to form plaques (flat and raised patches) up to several centimeters in diameter.

The center of the papule/plaque becomes darker in color and develops superficial (epidermal) changes such as blisters or crusting. The lesions usually evolve for 72 hours.

The typical lesion (also called iris lesion) of erythema multiforme has a sharp edge, regular round shape, and three concentric color zones:

  • The center is dark or dark red with a blister or scab
  • The next ring is pale pink and rises due to edema (fluid swelling)
  • The outermost ring is bright red.
  • The atypical target lesions show only two zones and an indistinct edge.

The eruption is polymorphic (meaning it is in many forms), hence the ‘multiform’ in the name. The lesions may be in various stages of development, with typical and atypical objectives present simultaneously.

A complete skin examination may be required to find specific goals since these may be few.

The lesions show the Köbner phenomenon (isomorphic), which means that they can develop in sites of anterior cutaneous trauma (but not simultaneous or later).

There is no associated swelling of the face, hands, or feet, even though these are common sites of rash distribution. However, the lips are often swollen, especially in greater erythema multiforme.

The commitment of the mucous membrane

Mucosal lesions, if present, usually develop a few days after the skin rash begins.

The mucous membrane involvement is absent or mild in minor polymorphous or multiform Erythema.

Changes in the mucosa, if present, initially consist of redness of the lips and inside the cheek. Sometimes blisters develop and break up quickly to form erosions and ulcers.

In larger erythema multiforme, one or more mucous membranes are usually affected, most often the oral mucosa:

  • More commonly, lips, inside the cheeks, tongue
  • Less naturally floor of the mouth, palate, and gums.

Other affected mucosal sites may include:

  • Eye
  • Anus and genitals
  • Trachea/bronchi
  • Gastrointestinal tract.

Mucosal lesions consist of swelling and redness with blistering.

The blisters break quickly and leave large, superficial, irregularly shaped, and painful ulcers covered by a whitish pseudomembrane.

Usually, the lips are swollen with hemorrhagic scabs. The patient may have difficulty speaking or swallowing due to pain.

Mucous membranes may be the only affected sites (mucositis). This can be serious and require hospitalization due to the difficulty of eating and drinking.

It has not been determined if this is a limited form of erythema multiforme. It is also known as Fuchs syndrome, and erythema multiforme of the mucosa may occasionally be due to recurrent herpes simplex.

Recurrent multiform Erythema

Erythema multiforme can be recurrent, with multiple episodes per year. It is believed that this is almost always due to HSV-1 infection.

How is the diagnosis of polymorph or multiform Erythema made?

Erythema multiforme is a clinical diagnosis, although a skin biopsy may be required to exclude other conditions. The histology of erythema multiforme is characteristic but not diagnostic. It varies according to the age of the lesion, its appearance, and the part of the biopsy.

Other tests may look for infections commonly associated with erythema multiforme, such as mycoplasma.

Consensus classification:

  • Minor multiform Erythema: smaller typical targets or elevated edematous papules distributed stubbornly.
  • Erythema multiforme major: typical primary objectives or elevated edematous papules distributed with the involvement of one or more mucous membranes; epidermal detachment involves less than 10% of total body surface area (ATSC)
  • SJS – Stevens-Johnson Syndrom (Stevens-Johnson Syndrome) / TEN – Toxic Epidermal Necrolysis (Toxic Epidermal Necrolysis): Generalized blisters that predominate on the trunk and face, presenting erythematous or pruritic macules and one or more erosions of the mucous membrane; the epidermal detachment is less than 10% of the total surface area of ​​the body for Stevens-Johnson syndrome and 30% or more for toxic epidermal necrolysis.

The mild form usually presents with mild itching (but can be very severe), pinkish-red spots, symmetrically arranged and starting at the extremities.

It often adopts the classic “target lesion” appearance, with a red-pink ring around a pale center. The resolution within 7-10 days is the norm.

Individuals with persistent polymorphous or multiform (chronic) Erythema will often have a minor injury, scratch, or abrasion form within a week.

Irritation or even pressure from clothing will cause the pain of Erythema to continue to spread along its margins for weeks or months, long after the original sore has healed in the center.

Who is affected by Polymorphic or Multiform Erythema?

Poliform erythema most often affects young adults (20-40 years). However, all age groups and races may be affected. There is a male predominance.

There is a genetic tendency to erythema multiforme. Specific issues are frequently found in people with erythema multiforme associated with herpes (HLA-DQw3) and recurrent erythema multiforme (HLA-B15, -B35, -A33, -DR53, -DQB1 * 0301).

Causes of Polymorphous Erythema

It has been reported that many suspected etiologic factors cause MS.

  • Infections: Bacterial (including vaccination with Bacillus Calmette-Guérin (BCG), hemolytic streptococci, legionellosis, leprosy, Neisseria meningitides, Mycobacteria, Pneumococcus, Salmonella species, Staphylococcus species, Mycoplasma pneumonia), Chlamydia.
  • Fúngico (Coccidioides immitis)
  • Parasite (Trichomonas species, Toxoplasma gondii),
  • Viral (especially Herpes Simplex)
  • Reactions to medications, most commonly to: antibiotics (including, Sulfonamides, Penicillin), anticonvulsants (Phenytoin, barbiturates), Aspirin, antituberculous, Allopurinol, and many others.
  • Physical factors: radiotherapy, cold, sunlight
  • Other: collagen diseases, vasculitis, non-Hodgkin lymphoma, leukemia, multiple myeloma, myeloid metaplasia, polycythemia

It is considered that the VHS is activating the minor MS in almost all cases. A herpetic etiology also accounts for 55% of the cases of central MS. Among the other infections, Mycoplasma infection seems to be a common cause.

It has been shown that the suppression of the herpes simplex virus and even prophylaxis (with acyclovir) prevents the recurrent eruption of erythema multiforme.


Polymorph or multiform erythema is often self-limiting and does not require treatment. The appropriateness of glucocorticoid treatment may be uncertain because it is difficult to determine if the course will be resolutive.

Treatment may be required for any possible cause, such as oral acyclovir (non-topical) for HSV or antibiotics (e.g., erythromycin) for Mycoplasma pneumonia. If a medication cause is suspected, the possible offensive medication should be discontinued.

Supportive/symptomatic treatment may be necessary.

Itching: oral antihistamines and topical corticosteroids can help.

Oral pain: mouth rinses containing local anesthetic and antiseptic reduce pain and secondary infection.

The participation of the eyes should be evaluated and treated by an ophthalmologist.

Erythema poliformo mayor may require hospital admission for supportive care, particularly if severe oral involvement restricts alcohol consumption.

The role of oral corticosteroids remains controversial, as no controlled study has shown any benefit. However, for severe disease, a measure of 0.5-1 mg/kg / d of prednisone (ol) is often used early in the disease process.

Recurrent erythema multiforme is usually treated initially with continuous oral acyclovir for six months at a dose of 10 mg/kg / d in divided doses (e.g., 400 mg twice daily), even if HSV has not been a trigger evident for the patient’s erythema multiforme.

This is effective in double-blind, placebo-controlled studies. However, erythema multiforme may reappear when acyclovir is stopped.

Other antiviral medications such as valaciclovir (500-1000 mg / d) and famciclovir (250 mg twice daily) should be tried if acyclovir has not helped.

Other treatments (used continuously) that have been reported to help suppress recurrent erythema multiforme include:

  • Dapsone 100-150 mg / day
  • Antimalarial drugs (e.g., Hydroxychloroquine)
  • Azathioprine 100-150 mg / day
  • Other: Thalidomide, Cyclosporine, Mycophenolate Mofetil, Photochemotherapy (PUVA)

What is the prognosis for erythema multiforme?

Minor polymorphous Erythema usually resolves spontaneously without leaving scars for 2 to 3 weeks. Erythema multiforme may take up to 6 weeks to resolve. Erythema multiforme does not progress to SJS / TEN.

There may be a residual discoloration of the mottled skin. Significant ocular involvement in more extensive polymorphous Erythema can rarely lead to severe problems, including blindness.